diff options
| author | Guenter Roeck <linux@roeck-us.net> | 2019-04-04 11:22:42 -0700 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2019-04-15 17:19:53 -0700 |
| commit | 8c0826756744c0ac1df600a5e4cca1a341b13101 (patch) | |
| tree | 2798eb6a92ce30f42c9517cc1d36f5fd2f74e0f9 | |
| parent | 755a9b0f8aaa5639ba5671ca50080852babb89ce (diff) | |
hwmon: (smsc47b397) Use request_muxed_region for Super-IO accesses
Super-IO accesses may fail on a system with no or unmapped LPC bus.
Also, other drivers may attempt to access the LPC bus at the same time,
resulting in undefined behavior.
Use request_muxed_region() to ensure that IO access on the requested
address space is supported, and to ensure that access by multiple drivers
is synchronized.
Fixes: 8d5d45fb1468 ("I2C: Move hwmon drivers (2/3)")
Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reported-by: John Garry <john.garry@huawei.com>
Cc: John Garry <john.garry@huawei.com>
Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
| -rw-r--r-- | drivers/hwmon/smsc47b397.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/hwmon/smsc47b397.c b/drivers/hwmon/smsc47b397.c index c0775084dde0..60e193f2e970 100644 --- a/drivers/hwmon/smsc47b397.c +++ b/drivers/hwmon/smsc47b397.c @@ -72,14 +72,19 @@ static inline void superio_select(int ld) superio_outb(0x07, ld); } -static inline void superio_enter(void) +static inline int superio_enter(void) { + if (!request_muxed_region(REG, 2, DRVNAME)) + return -EBUSY; + outb(0x55, REG); + return 0; } static inline void superio_exit(void) { outb(0xAA, REG); + release_region(REG, 2); } #define SUPERIO_REG_DEVID 0x20 @@ -300,8 +305,12 @@ static int __init smsc47b397_find(void) u8 id, rev; char *name; unsigned short addr; + int err; + + err = superio_enter(); + if (err) + return err; - superio_enter(); id = force_id ? force_id : superio_inb(SUPERIO_REG_DEVID); switch (id) { |